textproduct: Quad Cities

KEY MESSAGES

- Cold frontal passage will bring a risk of strong to severe storms through sunset.

- Outside of yet another system centered around Wednesday, mainly dry conditions should be seen until late next week.

SHORT TERM /THROUGH SATURDAY/

Issued at 153 PM CDT Fri Aug 21 2026

At 18z the cool front was located roughly from KY51 southwest to KIFA and near KEBS. Ahead of the front was a pre-frontal trof running from roughly KOVS to near KDSM. Satellite has agitated clouds along the front between KY51 and KDEH with showers a few storms developing. There is a layer of low to mid level steep lapse rates between the trof and front that will sweep through during the late afternoon/evening with some showers or storms along the pre-frontal trof. An associated upper level disturbance will help to enhance the overall mesoscale lift and maintain the showers/storms along the cool front.

The CAMs are struggling with what will happen late this afternoon/evening due to the overall weak forcing.

Based on what has occurred so far from satellite/radar, some low end convection will be seen along the pre-frontal trof. The stronger convection, associated with the upper level disturbance, will be tied to the passage of the cool front.

That being said, prime time for strong to severe storms looks to be 3 to 8 PM with the storms quickly decaying in the 8 to 10 PM time frame.

The primary risks still look to be damaging winds and hail. However, storm-scale interactions cannot fully rule out the potential of brief spin-up tornadoes.

The relatively higher severe risk still looks to be along/east of the Mississippi and the I-80 corridor on north.

After 10 PM quiet conditions will then be seen the remainder of the night with slowly falling dew points as the cool front slowly exits the area.

Seasonable temperatures will be seen on Tuesday with breezy conditions developing around mid-day.

LONG TERM /SATURDAY NIGHT THROUGH THURSDAY/

Issued at 153 PM CDT Fri Aug 21 2026

Saturday night through Friday Assessment...low (20-30%) confidence on rain around Wednesday

Northwest flow aloft will persist through the coming week. The best chance for any rain looks to be tied to around Wednesday during the passage of yet another cool front. However, this system will only have the moisture associated with it. As a result, the model consensus only has 20-30% chances for rain.

Prior to and after next Wednesday, there will be additional but weaker upper level disturbances moving through in the flow aloft. While an isolated shower or storm cannot be ruled out, over 90% of the area will likely remain dry with near seasonable temperatures.

AVIATION /18Z TAFS THROUGH 18Z SATURDAY/

Issued at 1212 PM CDT Fri Aug 21 2026

Pre-frontal trof and cold front to sweep through eastern Iowa and northern Illinois through 06z/22. CAMS are struggling in developing diurnal convection given areas of downward motion behind each boundary. Overall scenario supports a 30-50% coverage for convection with the better coverage along/east of the Mississippi.

DVN WATCHES/WARNINGS/ADVISORIES

IA...None. IL...None. MO...None.